Process of manufacturing an aluminum base grease



July .4, 1950 A. E. CALKINS PROCESS OF MANUFACTURING 4;: ALUMINUM BASEGREASE I Filed Dec. 8, 194a FL lEl DISI'ILLATE.

ALUMINUM SOAP ALUMINUM STEAIZATE) 4 Coolme To' 250-550" F.

NEuTRAL(F|N|sHEn) LUBRICATING Om NORMAL. FINISHING OPERATIONS QAPIDCOOLING To 'bETwEEN Acu: TIZEATMENT 5013A WASHING:

OVER NQOH EDISTILLATION Lu'bxzlcATme OIL. DISTILLATE. FROM OTHEROPEZATION'S' 'COOLED GREASE To PAcLAeEs CRYSE L ZATIQ IN PACKAGESSHIPMENT Gustav. E. Calida-s Ralph Glam. beer-bower @arle 159626 J w eg"Gina/enters Patented July 4, 1950 PROCESS OF MANUFACTURING AN ALUMINUMBASE GREASE Austin E. Calkins, Westfield, N. J.,, andRalph Barley, GlenBurnie, and Alan Beerbower, Baltimore, Md., assignors'to' Standard OilDevelopment Company, a corporation of Delaware Application December s,1948, Serial Ne. 64,164

1 Claim. 1

The present invention relates to a process of preparing an aluminumbasegrease. It relates more particularly to an aluminum soap thickenedlubricating grease prepared with mineral base lubricating oils so chosenand compounded that a stable grease of good texture and firm consistencyis obtained and is capable of being produced by rapid continuous orsemi-continuous processes. -In the prior art, a number of successfulaluminumfsoap-base greases have been prepared. Because of their smoothtexture and other desirable properties, aluminum soap greases have cometo be particularly favored for many uses, especially for the lubricationof chassis parts of automobiles, tractors, and the like. The prior arthas recognized certain difiiculties, however, in the preparation ofalminum soap greases, They pass through a peculiar transition stage incooling from grease cooking temperature to normal tem-, perature andahard, grainy and very unsatis factory structure is likely to resultunless 1) the cooling is conducted very slowly with careful control, or-(2) certain specific crystallization modifiers are employed to preventthe development of grainlness, etc., during the transition from arubbery structure to a smooth unctuous gel.

' In the older prior art it was considered essential to cool aluminumsoap greases ver carefully, for example by running the molten greaseinto shallow pans where cooling was allowed to progr'es's very slowly.This was a very slow and tedious process. More recently, as disclosed,for example, inn-the patent to Sproule and Zimmer, No. 2,394,- 567, andin the patent to Beerbower (one of the present inventors) and Zimmer,No. 2,449,580,-it hasbeenfound that modern rapid production methods maybe employed in making aluminum soap greases, provided crystallizationmodifiers such as alkylated mono-nuclear phenol or related materialssuch as resorcinol are used. Thus, in;

the Sproule and Zimmer patent, about 0.75% by weight of tertiary octylphenol is added to an aluminum soap grease and such grease may then beprepared by mixing lubricating oil and aluminum soap at a temperature ofabout 280 to 300 F., and then running the. hot mixture through a rapidchiller, e. g., a continuous close-clearance water-cooled chiller of thethin layer or scraped wall typel Similarly, a grease-containing about0.1 to 1% of resorcinol may be rapidly cooled as described in saidBeerbower and Zimmer patent.

The patented processes and products just described are quitesatisfactory, but the present in vention is based upon the discoverythat it is readily possible, by a choice of the particular types ofmineral lubricating oil employed, to make aluminum soap greases whichcan be rapidly chilled and which have excellent texture and and theproduct is found to be an excellent lubricating grease.

, Specifically, we have found that by the proper choiceand blending ofappropriate types of mineral lubricating oil which are readilyavailable, at least one of which contains as a natural ingredient apolar compound or group of compounds effective as suitablecrystallization modifiers, a. good aluminum soap grease may be prepared.The efficient continuous rapid cooling process may be used with suchmaterials. A lubricating oil distillate which, without finishing,contains active crystallization modifying material comprising alkylatedphenols, phenolic derivatives, naphthenic acids, 'etc., is commonlyobtained in the simple distillation of Venezuelan or Coastal type crudeoils, The quantity of such modifiers is common- 1y of the order of 1 to1.5% by weight, in the lubricating oil distillate. This is more than isdesired and more than is needed to modify the soap crystallization inthe rapid or close-clearance cooling process, and greases preparedsolely with this oil have very poor structures. Hence, according to thisinvention, it is necessary to dilute the untreated distillate with asuflicient quantityof refined or neutral oil which has been treated(acid, clay, caustic. selective solvent, or the like) to reduce the freeacid and phenolic content to very low values. The two oils are blendedto obtain a stock having a modifier content which is about 0.1 to 1%,preferably 0.25 to 0.75% by Weight, based on the finished grease. Theoptimum amount varies, depending upon the rapidity of cooling andintensity of mechanical working. Byadjusting the proportions ofunfinished distillate and neutral stock, the modifier content may beaccurately controlled within any reasonable desired limits.

While the exact composition of the modifier which is naturallypresent-in crude naphthenic Venezuelan or Coastal oils is not fullyknown, it appears to be a mixture of polar compounds, phenols, organicacids, and acid-phenol substituted aromatics, all of which are solublein potassium alcoholate or sodium hydroxide solution. These naturallyoccurring modifiers are effective to a very satisiactory degree formodifying the crystallization of aluminum soaps.

The extract from alkali treated oils may be used also by acidulating it.It contains modifiers of the same general type and may, under somecircumstances, be an economical process.

In the drawing, there is shown a flow diagram to illustrate thesimplicity and obvious advantages of the process more clearly. As showntherein, the Venezuelan or other naphthenic crude oil is subjected toordinary vacuum distillation to separate the lighter fuel distillate andthe heavier asphalt from the intermediate lubricating oil distillate,The lubricating oil distillate is then separated into two streams sothat part of it goes to the grease cooking unit while another part.issubjected to normal finishing operations, If desired, lubricating oildistillate from other operationsmay be brought into the normal finish:ing stage for acid treatment, soda washing, redistillation over sodiumhydroxide, and the like, as indicated above.

Ifhe finishedneutral stock is then taken to the cooker where it iblended, in suitable propore tions depending on the desired modifiercontent, with the unfinished distillate, and also. the aluminum stearateor other aluminum soap. Aluminum stearate is specifically preferred,but, other aluminum. soaps offatty acids of 12 to 22 carbon atoms suchas hydrogenated fish oil acids, for example, may. be used. The saturatedfatty acids oi this. range are preferred because of their superior.stability against oxidation. The propore tions oi finished andunfinished oils will usually be from about 1 to l parts by weight offinished or neutral stock combined with 10 to 2 parts by weightoi therawor unfinished oil. Thealuminum soap. content, based on the weight of thefinished fiease, is withinthe. limits of about 3% to 30 a range of 5150.15% being generally preferred.

As the ingredients are mixed, they are heated toa temperature of atleast 250 F. and may be heated as high as 350 F. The heating need-not belong continued. In the continuous process, for example, heating is onlymomentary, i. e., longenough for the ingredients to attain thetemperature of 250 F. to 350 F., with complete solvation, and. theheated mixture is then passed in continuous how. to the rapid cooler.

The rapid cooler, which maybe. of the close clearance type, waterjacketed, with or without scrapers-or a close fitting worm impeller, isarranged to bring the temperature downbelow the. normal transitiontemperature range of about 7,0? to 160 F'., for example to atemperature. of

between 7,0? and 100 F. From the cooler, the. product may be packageddirectly inasmuch as the final setting up and crystallization of thesoap: structure, which forms the body or framework'of the gel, takesplace very satisfactorily in the. final package.

Although the flow plan just described suggests using oil whichlby-passesthe finishing operation allies. wi h i hi h goes thr u he ish noperation, it will he self-evident that the finished stock may be anysubstantially neutral oil, derived from naphthenic or Coastal crude, ora Pennsylvania type oil. The latter, which is substantially neutral'whenremoved from the still, commonly will require no finishing treatment.The product of the invention thus may comprise various types of neutralor substantially neutral stock combined with the unfinished naphthenicoil.

Example As an example of the operation of this invention, the followingmay be cited: An unfinished Venezuelan distillate (from Lagunillascrude) and a finished Coastal distillate were selected as the two oilcomponents. These oils had the following characteristics:

Untreated F 25 3:? fi flg Lubricating Viscosity at F. (SSU) 1214 916Viscosity at 210 F. (SSU) 78. 4 70. 5 Gravity (A)? 18.2 23.1 FlashPoint, F. (Open Cup)- 45 450 Pour Point. F. (ASTM), +5 0 SapcnificationNo 1 2.1 0.14 Color'(Tag-Robinsom un Below 1 10% Cast (Color byreflected light) Blue-Green Blue These oils were then mixed with acommercial aluminum stearate in the following proportions:

Ingredient: Per cent by weight Aluminum stearate 6.00 Venezuelandistillate y, 62.30; Finished Coastal oil 31,70

Unwork-ed penetration (ASTM) 2,14 Worked penetration (ASTM) 326 1800strokes worked penetration 3,2; ASTM penetration after passage through ah gh pressure grease un 340 ppearance. emi-transpar nt Oil separation(.6 months at 77 1?.) None.

The grease was subjected to all the conventional quality tests forpressure gun applicat'en, andwas found to be very satisfactory.

It isobvious that the proportions of the treated and untreated oils maybe varied and the quanti ties and types of soaps, or the fattymaterials:

from which they are formed may be selected as desired. The conventionalmodifiers such as antia.

oxidants, extreme pressure additives, tackiness.

, agents, corrosion inhibitors, etc., maybe employed if desired.

What is claimed is:

The process of preparing stable aluminum-base lubricating greases ofsmooth texture which com prises combining about 62 by weight ofunfinished Venezuelan distillate mineral oil of lubricating oilviscosity and" containing about 1 to by weight of polar compoundsincluding phenols, naphthenic acids, and acid-phenol substituted?aromatic compounds'with about32 of fin-ished:

Coastal oil as a diluent and about 6% of aluminum soap of substantiallysaturated fatty acid within the range of 12 to 22 carbon atoms as athickener, heating the mixture to a temperature of above 300 F. and nothigher than about 350 F., and thereafter rapidly cooling below about 100F. in thin layers, accompanied by mechanical working.

AUSTIN E. CALKINS. RALPH DARLEY. ALAN BEERBOWER.

1 8 REFERENCES CITED The following references are of record in the fileof this patent:

UNITED STATES PATENTS Number Name Date 1,804,124 Southard May 5, 19311,902,635 Gebharclt Mar. 21, 1933 2,380,893 Zimmer et a1 July 31, 194510 2,431,453 Beerbower et a1. Nov. 25, 1947

